Field of the Invention
The present invention relates to a producing method of a wired circuit board and a wired circuit board produced by the method.
Description of Related Art
Conventionally, a wired circuit board such as a suspension board with circuit has included a metal supporting layer, an insulating layer that is formed on the metal supporting layer, and a conductive pattern that is formed on the insulating layer. In the wired circuit board, when there is a defect in the conductive pattern, the connection reliability is reduced and therefore, the presence or absence of a defect of the conductive pattern has been inspected.
In the inspection, an AOI (automated optical inspection) device in which the presence or absence of a defect of the conductive pattern is judged by allowing inspection light to enter the conductive pattern to detect the inspection light that is reflected from the conductive pattern has been used.
For example, a producing method of a thin film multilayer board has been disclosed (ref: Japanese Unexamined Patent Publication No. H02-94594). In the method, laser light is applied to a thin film multilayer board having an insulating film and a wiring pattern that is formed on the insulating film with the laser light narrowed down by a condenser lens to detect reflected light, so that a defect and the like in the wiring pattern is judged.
In this method, the laser light having a wavelength of 450 nm or less is used so as to increase the difference of reflectance between the wiring pattern and the insulating film.